The high-mass protostars IRS 9A-C

Zoom-in view to the Starburst Region NGC 3603 IRS 9. The brightest members of the spares association of protostars are IRS 9A-C. The intrinsic brightness of these nascent stars is impressive: 100,000, 1000 and 1000 times that of the Sun for IRS 9A, IRS 9B and IRS 9C, respectively. Their brightness and infrared colours give information about the physical properties of these protostars. They are very young in astronomical terms, probably less than 100,000 years old. They are already quite massive, though, more than 10 times heavier than the Sun, and they are still growing.